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Steel T6 vs T8

Steel · grade comparison

Steel T6 and T8 are both steel grades. Both yield at about 590 MPa — strength does not separate them. T8 is the more ductile: elongation 15% versus 12% for T6, and T6 is harder (262 HB vs 240 HB). T8 is lighter (8.6 g/cm³ vs 8.89 g/cm³ for T6) and T6 runs hotter in service (500°C vs 400°C continuous). On the shop floor, T8 machines more easily (fair vs poor) and T8 sits in a lower cost tier (premium, $$$) than T6 (high, $$$$).

T6Choose it when the part sees heat.

T8Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

T6 vs T8: properties

T6T8

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

86 GPa12.5 Msi
85 GPa12.3 Msi

Bulk Modulus

160 GPa23.2 Msi
170 GPa24.7 Msi

Yield Strength (0.2% offset)

590 MPa85.6 ksi
570 MPa82.7 ksi

Elongation at Break

12%
15%

Reduction in Area

22%
25%

Compressive Strength

1,400 MPa203 ksi
1,200 MPa174 ksi

Shear Strength

560 MPa81.2 ksi
—

Charpy V-Notch Impact (RT)

12 J8.9 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

262 HB
240 HB

Hardness, Rockwell B

100 HRB
99 HRB

Hardness, Vickers

275 HV
250 HV

Same in both: Elastic (Young's) Modulus 220 GPa31.9 Msi · Poisson's Ratio 0.29 · Tensile Strength (Ultimate) 900 MPa131 ksi

Physical

Density and transition temperatures.

Density

8.89 g/cm³0.32 lb/in³
8.6 g/cm³0.31 lb/in³

Liquidus Temperature

1,480°C2,696 °F
1,460°C2,660 °F

Same in both: Melting Point (Solidus) 1,400°C2,552 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Expansion (CTE, 20–100 °C)

10.8 µm/m·K6 µin/in·°F
11.2 µm/m·K6.2 µin/in·°F

Max Service Temperature (continuous)

500°C932 °F
400°C752 °F

Min Service Temperature

-50°C-58 °F
-40°C-40 °F

Same in both: Thermal Conductivity 22 W/m·K12.7 BTU/hr·ft·°F · Specific Heat Capacity 420 J/kg·K0.1 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 3.1 % IACS · Electrical Resistivity 5.5×10⁻⁷ Ω·m21.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.55 V
-0.6 V

Corrosion Resistance

15 / 100
18 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

25 / 100
35 / 100

Machinability Rating (AISI 1212 = 100 %)

30%
40%

Weldability

12 / 100
15 / 100

Formability (cold)

20 / 100
12 / 100

Castability

25 / 100
—

Polishability

65 / 100
70 / 100

Same in both: Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

90 MJ/kg38,693 BTU/lb
60 MJ/kg25,795 BTU/lb

Embodied Carbon (primary production)

6.5 kg CO₂/kg
4.2 kg CO₂/kg

Embodied Water

220 L/kg26.4 gal/lb
90 L/kg10.8 gal/lb

Typical Recycled Content

40%
35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

101 kN·m/kg
105 kN·m/kg

Specific Stiffness (E / density)

24.7 MN·m/kg
25.6 MN·m/kg

Modulus of Resilience

791 kJ/m³
738 kJ/m³

Thermal Diffusivity

5.9 mm²/s
6.1 mm²/s

Same in both: Thermal Shock Resistance Index 8

Strength versus weight

Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleT8T6

Manufacturing and finishing

CapabilityT6T8
CNC machining—Yes
Default condition—Annealed
Relative cost$$$$ High$$$ Premium
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

T6 vs T8 — frequently asked

What is the difference between T6 and T8?

Steel T6 and T8 are both steel grades. Both yield at about 590 MPa — strength does not separate them. T8 is the more ductile: elongation 15% versus 12% for T6, and T6 is harder (262 HB vs 240 HB).

Which is cheaper, T6 or T8?

T8 is the lower-cost material: it sits in the premium tier ($$$) while T6 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, T6 or T8?

T8. Its machinability rates fair (35/100) against poor (25/100) for T6.

Ready to make it?

Upload a CAD file and FabDigit prices the part in T6 and T8 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.